Shop Running Rigging
How To Choose The Right Line
How do you decide which line is best for your application?
Selecting the right running rigging for your sailboat can be compared with choosing the right beer for your fridge or the best ice cream for your freezer. Okay, it’s a little more complicated and technical than picking a brew or a dessert. There are a lot of choices, and your selection is often more a matter of taste than function. Competing manufacturers offer similar products, like the Endura Braid, Warpspeed and XLS Extra.
1. Decide which construction style of line is best for your purpose.
2. Check the breaking strength and diameter
Consider that hand-adjusted lines feel most comfortable to grip at about 5/16" to 3/8" diameter. Other parts of a purchase system such as a cascade vang can possibly be smaller diameter. The most highly-loaded purchases may need super-strong low stretch line. If your application will include knots, remember that many high-tech lines suffer about a 50 percent reduction in their working loads when tied, instead of spliced. Knowing how to splice is a useful rigging skill. If you haven’t acquired that talent yet, West Marine Rigging offers splicing services.
3. Match the diameter of the line to the application.
Greater line holding working loads are achieved by increasing the diameter of the line. If necessary, consider asking West Marine Rigging to customize the line, sleeving the line or inserting core in the rope clutching area to increase the diameter and line-holding performance.
4. Know the fibers, and what they do best.
How much stretch can you tolerate? Polyester is supple, strong, economical but stretchy. Dyneema doesn’t stretch—it creeps. Polypro is light but less durable, and Vectran is strong enough to lift a Chevy truck, but more costly.
5. Check the Line Selection Guide
below for some recommended choices. Don’t be afraid to be creative and experiment. Look at other boats that are well rigged and borrow the good ideas you encounter. Have fun while you make your boat easier to sail!
Running Rigging Fiber Guide
Workhorse line fiber and the durability champ for decades, but stretchier than newer fibers. Holds color well and has great abrasion resistance. Perfect cover for double braid lines, protecting low-stretch cores from UV radiation and chafe. Polyester double braid like Sta-Set works great for frequently adjusted lines, like main and jib sheets, or moderately loaded control lines. Very flexible, easy to handle, polyester is still the fiber of choice for most applications on cruisers and club racers.
Almost no stretch, no creep, and absorbs little water. Works reliably at a high percentage of its breaking strength, so it’s great for highly loaded applications. Like Technora, Vectran is among the strongest core materials available. UV resistance and durability is moderate. Often used for upwind sail halyards under static loads, like permanently hoisted roller-furling headsails. Used both stripped and covered, for highly loaded purchase systems and travelers, and other no-stretch applications.
Dyneema / High-Modulus Polyethylene (HMPE)
Several patented variations of this fiber have slightly different characteristics, but Spectra-Dyneema-HMPE has the highest strength-to-weight ratio, low stretch, and impressive maximum working loads. Very slippery with good hand, but poor knot-holding ability and a low melting point (300°F). Does not absorb water, but it will experience gradual “creep” or permanent elongation under sustained static load. Good core upgrade from polyester double braid, with almost no stretch. Often used uncovered, or with a polyester cover where it encounters a cleat or the drum of a winch. Great in multi-part purchase systems, or for replacing 7x19 wire in trapeze lines. A very popular line with excellent longevity; it is also light, so it floats. Newest, strongest, lowest stretch, and with nearly zero creep are Dyneema lines made from a variant called SK-90. It stretches 10-15 percent less than the most common type of Dyneema, SK-75, and is also 10-15 percent stronger. New England Ropes’ STS-12 SK-90 and Dinghy Star (from FSE Robline) are two ropes made with this fiber.
Very low stretch and no creep. Like Kevlar, Technora has poor internal abrasion tolerance, fair chafe resistance, and is damaged by UV light. Blending with another fiber, like Dyneema SK-75 in the core of T-900 line, helps reduce the durability problems associated with Technora, and lets its strengths shine. Technora needs protection with a polyester cover, or coating on the core, if stripped.
A light, relatively inexpensive, relatively stretchy fiber, polypropylene is frequently blended with other fibers like Dyneema to add bulk for easy handling. Samson uses this combination in their XLS Extra-T braid, which is stronger and lighter than polyester, but less costly than 100 percent Dyneema. Polypropylene floats and doesn’t absorb water, but has poor UV resistance. Its stretch is similar to polyester, so it works well for sheets, especially light-air spinnaker sheets, dinghy main and jib sheets, and other frequently adjusted control lines. Durability is not its strong suit, so more frequent replacement is needed.